1. Field of the Invention
The present invention relates to an ophthalmologic imaging apparatus such as a fundus camera which controls the light amount to be received by an image sensor.
2. Description of the Related Art
A conventional ophthalmologic imaging apparatus is known, which radiates imaging light such as visible light onto the fundus of a subject's eye and receives reflected light therefrom to capture a fundus image. Since the reflectance of the fundus differs for each subject's eye because of individual difference and pathological changes, there is provided a technique for suitably controlling the light amount of imaging light to be received by an image sensor.
As an example of such a technique, Japanese Patent Application Laid-Open No. 04-150831 discusses a technique for determining the light amount of visible light (imaging light) based on infrared light radiated onto a subject's eye and reflected by the fundus. However, this technique has a problem that the optic papilla is over-exposed in the captured fundus image since its large reflectance is not taken into consideration.
Japanese Patent Application Laid-Open No. 2005-270152 discusses a technique for setting the light amount with which the optic papilla is not over-exposed as the light amount of visible light (imaging light), based on the light amount of reflected visible light from the optic papilla of the fundus out of visible light radiated onto a subject's eye. This technique has a problem that visible light radiation before imaging causes myosis of the subject's eye.